title: Central administration of prolactin-releasing peptide shifts the utilities of metabolic fuels from carbohydrate to lipids in chicks.
abstract: We have recently identified prolactin (PRL)-releasing peptides (PrRPs) and their stimulating effects on feeding behavior in chicks. To investigate further metabolic functions of PrRP, the present study was performed to clarify whether intracerebroventricular (ICV) injection of PrRP31, an active form of PrRP in chicks, affects heat production (HP), respiratory quotient (RQ) and plasma concentrations of metabolic fuels in chicks. The ICV injection of PrRP31 (94 and 375 pmol) did not affect HP but significantly lowered RQ. The change in RQ implies that PrRP31 shifted the utility of metabolic fuels in the body. This idea was confirmed by subsequent results in which ICV injection of PrRP31 significantly reduced glucose but increased non-esterified fatty acid concentrations in plasma. These shifts in blood metabolic fuels would not be through the increased plasma insulin, because the ICV injection of PrRP31 significantly decreased plasma insulin concentration. On the other hand, ICV injection of another orexigenic peptide, neuropeptide Y (NPY) also induced the insulin release and the metabolic effects were similar to those of PrRP31. Because ICV injection of PrRP31 increased NPY mRNA in the diencephalon, the NPY may mediate the metabolic functions of PrRP31. In summary, the present study suggests that central PrRP31 shifts the utilities of peripheral energy sources, which is not via hyperinsulinemia but via the diencephalon.
authors.affiliation: Department of Agrobiological Science, Faculty of Agriculture, Ehime University, Matsuyama, Ehime 790-8566, Japan. Electronic address: tetsu@agr.ehime-u.ac.jp.
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Tachibana
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Moriyama
authors.forename: Md Sakirul Islam
authors.initials: MS
authors.lastname: Khan
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Sakamoto
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001786:Blood Glucose / Q000378:metabolism; D050260:Carbohydrate Metabolism / Q000187:drug effects*; D002245:Carbon Dioxide / Q000378:metabolism; D002645:Chickens / Q000502:physiology*; D004027:Diencephalon / Q000187:drug effects / Q000378:metabolism; D005230:Fatty Acids, Nonesterified / Q000097:blood; D007276:Injections, Intraventricular; D007328:Insulin / Q000097:blood; D050356:Lipid Metabolism / Q000187:drug effects*; D008297:Male; D009478:Neuropeptide Y / Q000096:biosynthesis / Q000494:pharmacology; D010101:Oxygen Consumption / Q000187:drug effects; D056690:Prolactin-Releasing Hormone / Q000008:administration & dosage / Q000494:pharmacology*; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D022722:Thermogenesis / Q000187:drug effects; D014280:Triglycerides / Q000097:blood
chemical_list: D001786:Blood Glucose; D005230:Fatty Acids, Nonesterified; D007328:Insulin; D009478:Neuropeptide Y; D056690:Prolactin-Releasing Hormone; D012333:RNA, Messenger; D014280:Triglycerides; D002245:Carbon Dioxide
keywords: Chick; Heat production; Insulin; Intracerebroventricular; Prolactin-releasing peptide; Respiratory quotient